docs: def save(self, file_or_wfs, filename, overwrite=False):
          '''
          Save a file-like object or a `werkzeug.FileStorage` with the specified filename.
  
          :param storage: The file or the storage to be saved.
          :param filename: The destination in the storage.
          :param overwrite: if `False`, raise an exception if file exists in storage
  
          :raises FileExists: when file exists and overwrite is `False`
          '''
          self.write(filename, file_or_wfs.read())
          return filename